请帮我看看为什么我的FC5系统下，PPP0无法激活？

我的电脑里面又XP和Fedora core5两套操作系统。现在在fc5下面发现ppp0无法激活不知道是怎么回事?

这里时LINUX系统下的配置过程以及相应结果：
[root@localhost ~]# vi /etc/sysconfig/network
NETWORKING=yes
HOSTNAME=localhost.localdomain

[root@localhost ~]# vi /etc/sysconfig/network-scripts/ifcfg-eth0
# Realtek Semiconductor Co., Ltd. RTL-8139/8139C/8139C+
DEVICE=eth0
BOOTPROTP=dhcp
HWADDR=00:01:80:40:2E:9C
ONBOOT=yes

[root@localhost ~]# /etc/rc.d/init.d/network restart
正在关闭接口 eth0： [确定]
关闭环回接口： [确定]
弹出环回接口： [确定]
弹出界面 eth0： [确定]

[root@localhost ~]# rpm -qa|grep rp-pppoe
rp-pppoe-3.5-31
[root@localhost ~]#/usr/sbin/adsl-setup
Welcome to the ADSL client setup. First, I will run some checks on
your system to make sure the PPPoE client is installed properly...

The following DSL config was found on your system:

Device: Name:
ppp0 DSLppp0

Please enter the device if you want to configure the present DSL config
(default ppp0) or enter 'n' if you want to create a new one:
LOGIN NAME

Enter your Login Name (default hjzy10068):

INTERFACE

Enter the Ethernet interface connected to the ADSL modem
For Solaris, this is likely to be something like /dev/hme0.
For Linux, it will be ethX, where 'X' is a number.
(default eth0):

Do you want the link to come up on demand, or stay up continuously?
If you want it to come up on demand, enter the idle time in seconds
after which the link should be dropped. If you want the link to
stay up permanently, enter 'no' (two letters, lower-case.)
NOTE: Demand-activated links do not interact well with dynamic IP
addresses. You may have some problems with demand-activated links.
Enter the demand value (default no):

DNS

Please enter the IP address of your ISP's primary DNS server.
If your ISP claims that 'the server will provide dynamic DNS addresses',
enter 'server' (all lower-case) here.
If you just press enter, I will assume you know what you are
doing and not modify your DNS setup.
Enter the DNS information here: 211.166.0.166
Please enter the IP address of your ISP's secondary DNS server.
If you just press enter, I will assume there is only one DNS server.
Enter the secondary DNS server address here: 211.166.0.168
PASSWORD

Please enter your Password:
Please re-enter your Password:

USERCTRL

Please enter 'yes' (three letters, lower-case.) if you want to allow
normal user to start or stop DSL connection (default yes):

FIREWALLING

Please choose the firewall rules to use. Note that these rules are
very basic. You are strongly encouraged to use a more sophisticated
firewall setup; however, these will provide basic security. If you
are running any servers on your machine, you must choose 'NONE' and
set up firewalling yourself. Otherwise, the firewall rules will deny
access to all standard servers like Web, e-mail, ftp, etc. If you
are using SSH, the rules will block outgoing SSH connections which
allocate a privileged source port.

The firewall choices are:
0 - NONE: This script will not set any firewall rules. You are responsible
for ensuring the security of your machine. You are STRONGLY
recommended to use some kind of firewall rules.
1 - STANDALONE: Appropriate for a basic stand-alone web-surfing workstation
2 - MASQUERADE: Appropriate for a machine acting as an Internet gateway
for a LAN
Choose a type of firewall (0-2): 0

Start this connection at boot time

Do you want to start this connection at boot time?
Please enter no or yes (default no):

** Summary of what you entered **

Ethernet Interface: eth0
User name: hjzy10068
Activate-on-demand: No
Primary DNS: 211.166.0.166
Secondary DNS: 211.166.0.168
Firewalling: NONE
User Control: yes
Accept these settings and adjust configuration files (y/n)? y
Adjusting /etc/sysconfig/network-scripts/ifcfg-ppp0
Adjusting /etc/resolv.conf
Adjusting /etc/ppp/chap-secrets and /etc/ppp/pap-secrets
(But first backing it up to /etc/ppp/chap-secrets.bak)
(But first backing it up to /etc/ppp/pap-secrets.bak)



Congratulations, it should be all set up!

Type '/sbin/ifup ppp0' to bring up your xDSL link and '/sbin/ifdown ppp0'
to bring it down.
Type '/sbin/adsl-status /etc/sysconfig/network-scripts/ifcfg-ppp0'
to see the link status.

[root@localhost ~]# /sbin/ifconfig
eth0 Link encap:Ethernet HWaddr 00:01:80:40:2E:9C
UP BROADCAST MULTICAST MTU:1500 Metric:1
RX packets:0 errors:0 dropped:0 overruns:0 frame:0
TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:0 (0.0 b) TX bytes:0 (0.0 b)
Interrupt:18 Base address:0x8000

lo Link encap:Local Loopback
inet addr:127.0.0.1 Mask:255.0.0.0
inet6 addr: ::1/128 Scope:Host
UP LOOPBACK RUNNING MTU:16436 Metric:1
RX packets:2354 errors:0 dropped:0 overruns:0 frame:0
TX packets:2354 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:2602615 (2.4 MiB) TX bytes:2602615 (2.4 MiB)

系统根本就无法激活PPP0
把DNS改成211.166.15.23以后，不仅ppp0无法激活，连eth0也无法激活了。
到底是那里的问题呢？
我前段时间用网通一直是这样配置的，没有任何问题，只是最近换了长城互联网才这样。我的电脑没有进行任何改动。网卡也是最普通的RTL-8139/8139C/8139C+。我已经被这个问题困扰了很久了。麻烦各位大哥大姐帮我看看:time:1 :0(1
内核是Fedora core(2.6.15-1.2054_FC5)